Aircraft



March 5, 1935.-

E, A: STALKER 1,993,419

AIRCRAFT Filed Aug. 19, 1931 Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE AIRCRAFT Edward A. Stalker, Ann Arbor, Mich. Application August '19, 1931, Serial No. 558,043 20 Claims. (.01. 244-12) My' invention relates to aircraft wherein a means is provided to remove the boundary layer by a wind driven pump; and the objects of my invention are first, to provide an eflicient means of actuating the pump by a turbine located within the wings and, secondly, toprovide a means of causing a large flow of air through ,the turbine even when the speed of the airplane is small.

A further object is to provide a means of pumping which is subdivided to furnish varying degrees of flow to various parts of the airplane:

Other objects are to provide unique pumping means and structural arrangements of the wing which have a wide range of application.

I attain these objects by the mechanism illustrated in the accompanying drawing in which Figure 1 is a vertical section through the wing; Figure 2 is a plan view of the wing. Figure 3 is a vertical section through the wing '20 along the broken line AA. 7

Similar numerals refer to similar parts throughout the several views.

It is well known in-the science of aerodynamics that the removal of the boundary layer permits 25 an increase in lift and a decrease in drag. The means I have provided for removing the boundary layer consists of a wind turbine 1 located within the wing 2 and whose blades 3 are interposed between the entrance 4' and exit 5 of a passage 6 30 within the wing. In-fact the blades 3 are near the smallest section 7 of the passage 6 and as the turbine rotates successive blades pass across the small cross section'bf the passage 6. As shown in Figure 2 more than one inlet 4 may be used 35 to conduct air to the turbine blades. Each inlet is continued by tube walls up to the turbine rotor. The turbine blades rotate across the tube and the flow in theinlet passes from the blades into a branch of the exit tube 6.

The exit of the Venturi passage 6 is formed by a flap 8 which is rotatable about a forward hinge 9. Rotation is accomplished by the horn 10, link 11 and a suitable bell crank mechanism 12 similar to those now used for ailerons in con- 45 ventional airplanes} The exit 5 may be closed or opened at the will of the pilot. When the exit is closed the wing contour is normal andso presents very little resistance to the air. By a wing contour is'meant an airfoil section which when normal is characterized by a smoothly changing outline terminating in a relatively thin trailing edge. g

.The flap 8 may be opened to such an extent that 55 the exit width at 5 is greater than the thickness friction and vibrations.

of the wing at the flap hinge. This has a very beneficial effect because by spreading out the flow over the wing as it reaches the trailing edge there is a very appreciable increase in the suction at the exit 5. There will then be a greater flow through the passage 6. E

It is also advantageous to have the flap on the under surface of the wing for then the increase of suction at 5 causes the air flowing over the upper surface to'follow the surface more closely, consequently the flow receives a greater de- 10' flection downward which results in higher lifting power for the wing. I v

The blades 3 of the turbine are those on the outer periphery of the rotor. The inner blades 13 constitute the low pressure pump which draws 15 air principally from the aft portion of the wing. The outer blades 3 of the turbine also constitute the high pressure pump, because when the-blades are outside the throat of the Venturi they induce a flow between the walls 14 and 15 as seen in Figure 1. The air is discharged through'thepassage 16 or through '17. The air discharged through 17 is of high velocity and accelerates the boundary layer which is similar in eifect to removing it. In fact to remove the boundary layer by any means, kinetic energy must be added to it in the form of velocity. The passage 17 is closed at the tip of the wing so that the flow is entirely out the slot 20 and is directed tangentially rearward along the wing surface. At the rotor end, the passage 17 extends around the periphery except for the passages 4. The passage 16 is open to the under side of the fan and is also open to the atmosphere at the wing tip as indicated by the flow in Figure 2. Instead of. the flow of 16 being directed out the tip it might be'directed to other localities of the wing surface.

Since the air is drawn in through the wing openings by the blades 13 and the same air is forced out the openings 17 by the blades 3, the 40 combination of the pumping means 13 and 3 is in effect a two stage blower. Both stages serve to add kinetic energy to the boundary layer.

In my patent, Airplane wing, No. 1,691,942, November 20,1928, I show a turbine wholly en- 45. closed within the throat of the Venturi. Calculations indicate that-the rate of rotation, necessary to abstract the desired amount of energy from the flow, would be excessive because of I In other words the tip speeds of the blades would be excessive if the flow went through all the blades of the turbine simultaneously. This difficulty is. obviated by disposing a series of bladesabout the periphery of a large diameter rotor, and then letting the blades move successively into the energizing flow at the Venturi throat.

A second purpose is also served because the.

pump bladesmay be constructed at the center of the turbine rotor, and the turbine blades themselves also may be used as high pressurepump blades. This will reduce the weight and comfrom a given flow of air from sixteen twentys'venths to one hundred per cent ideally. For the expansion tube to be emcient it must be closed against undue influx of air which would raise the pressurein the tube in advance of the exit where the static pressure is supposed to just reach that of the surrounding medium. In passing the turbine wheel the static pressure is low but the dynamic pressure is high. For this reason I provide a tube or passage with walls substantially closed to obnoxious sourcesof pressure. It is possible,

' however, as pointed out in my Patent No. 1,829,616

dated October 27,. 1931, entitled Aircraft, to use openings in the walls of the expansion tube to I energize the boundary layer on the tube walls.

Such energization would prove beneficial, and can not be classed'as an obnoxious influx of air.

Sincethe theory of operation is to add energy to the'boundary layer there is a distinct advantage to have the air from the turbine passage discharged to the rear of the induction openings because then the blower does not need to handle the air which has lost itsenergy in going through the turbine.

Openings suitable for the energization of the boundary layer are relatively small in achordwise direction and are distributed along a substantial section of the span, preferably to within about one chord length of the wing tip; and in the limiting case, the openings may be so close together as to'form a continuous slot...

While the forms of this apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these exact forms. Many of the features of the wing, and power and pumping means are applicable to other power means than the wind-driven turbine. That is, changes may be made herein without departing from the scope of the invention which is defined in the appended claims.

I claim:

1. A wing having a passage through a portion thereof with the exit of the passage facing substantially downstream, a turbine operated by the flow of fluid 'in thepassage through successive groups of the turbine blades, openings in the wing surface and a means, operated by the turbine, to cause a flow through said openings.

3. A wing having a passage through a portion thereof, a turbine whose blades pass successively into and out of the passage, openings in the wing surface and pumping means operated by the turbine to cause a flow through said openings.

4. A wing having a passage through a P0111011 thereof, a turbine whose blades pass successively into and out of the passage, openings in the wing surface and pumping means operated by. the turbine to cause an outward flow through said openings.

5. A wing having a. passage through a. portion thereof, a turbine operated by the flow of air through the passage, and'conduit means to use the turbine blades as the blades of a pump- 6. A wing having a passage-through a portion thereof, openings in the surface of the wing, a turbine'operated by the flow of air through the passage, and a two stage blower formed in the turbine rotor to cause a flow through the openings in the wing.

'7. A wing having a passage-through a portion thereof, openings in the surface of the wing, a turbine operated by the flow of air through the passage, a suction fan formed in the center of the turbine rotor, and a pressure fan formed in an outer annulus of the rotor, constituting means to cause an inward flow of air through some of-25 the openings, and an outward flow of air through other openings in the wing surface.

8. In a wing associated with a relative flow of fluid and having a passagetherethrough from the under surface to an exit formed between the upper surface and a lower surface element, and opening in the upper surface for boundary layer energization, a plurality of blades rotatable in a plane substantially parallel to the chordwise' extent of the wing with some blades in the passage, 'and conduit means cooperating with other blades and the upper surface opening to cause a flow therethrough.

9. In a wing of substantially closed nose and associated with a flow of fluid and having an opening in the upper surface for energizing the boundary layer; a passage having an exit formed between the upper and lower surface of the wing,

a prime mover in the passage and actuated by the flow therein, and a means of pumping in com munication with the upper surface opening and driven by the prime mover to cause a flow through the upper surface opening.

10. In a" wing associated with a flow of fluid and having an opening in the upper surface for energizing the boundary layer; a passage associated with a flow of fluid and extending through the wing to an exit facing'rearward formed between the upper and lower surface of thawing, said passage comprising an expansion tube and a throat closed against the upper surface opening, a prime mover actuated by the flow in the passage, and a means of pumping in communication with the upper surface opening and driven by vthe prime mover to cause .a flow through the upper surface opening.

11. In a wing associated with a relative flow of fluid and having an opening in the upper surface for energizing the boundary layer; a passage of substantially closed surface having an inlet opening in the lower surface and a rearward facing exit formed between the upper surface and a lower surface of the wing, a prime mover in communication with the upper surface opening and utilizing the energy in the passage flow, a means of pumping motivated bythe prime mover to cause a flow through the upper surface opening.

12. In a wing having a substantially closed nose and an opening in the upper surface for boundary layer energization; a passage associated with a flow of fluid and extending through from the under surface to an exit formed between the upper surface and thelower surface of the wing, said passage comprising an expansion tube leading from a throat whose sides are substantially closed to communication with the upper surface opening; a prime mover in the passage and actuated by the flow in the passage, anda means of pumping in communication with the upper surface opening and driven by the prime mover to the passage; a means of pumping in communiea tion with the upper surface opening, mot vated by the prime mover to cause a flow through the upper surface opening.

14. In a wing associated with a flow of .air and possessing an opening in the upper surface for boundary layer energization, a turbine wheel, and

an element able by its movement relative to the aircraft to lower the pressure in a region; a means of pumping actuated by the turbine wheel, a conduit communicating between the means of pumping and the upper surface openings and means to move the element so as to expose the turbine to a stream of air flowing rearward substantially along the wing chord to the region of lowered air pressure.

15. In combination of a wing, a means of pumping, induction openings in the surface of the wing for the intake of air by the piunping means, a

discharge opening for emitting the air, and means to divide the inducted air into streams so that one stream may be further compressed before being discharged through the discharge opening.

16. In a wing associated with a relative flow of air and having a nose surface in major part closed to the head on impact of the air flow, walls defining a passage having access to the impact pres- -sure of the air flow and extending through the wing to an exit formed between the upper surface and an element of the lower surface of the wing, said passage having walls diverging in plan view so as to form an expansion tube, a perforated surface of the wing to form an opening for use in energizing the boundary layer, a means of a pumping in communication with said opening to cause a flow therethrough, and a prime mover in the said passage and deriving energy from the flow therein to actuate the means of pumping.

17. In a wing associated with a relative flow of air, means defining upper, lower and side walls to form in the wing a passage having below access to the impact pressure of the air flow and extending to a rearward facing exit formed between the upper surface and an element of the lower surface of the wing, a perforated surface of the wing to. form a rearward directed discharge opening for use in energizing the boundary layer, a means of pumping in communication with said discharge opening to discharge a how therethrough, ,aprime mover in said passage and deriving energy from the flow therein to actuate the means of pumping, and means to close the passage exit so as to form a tapered aft end to the wing.

18. In a wing associated with a relative flow of air, means defining upper, lower and side walls to form a passage having a constricted cross section, said passage having access to the impact pressure of the air flow and extending to a rearward facing exit formed between the upper surface andan element of the lower surface of the.

wing, a perforated surface of the wing to form an opening for use in energizing the bounary layer,

a means of pumping in communication with said opening to cause a flow therethrough, a prime mover in said passage and deriving energy from the flow therein to actuate the means of pumping, the said passage having at its narrowest cross section a periphery transverse to the flow therein closed in major part to communication with the said upper surface opening.

19. In a wing associated with a relative flow of air, w'alls defining a passage through the wing,

said passage having access to the impact pressure of the airflow and an exit facing rearward formed between the upper surface and an element of the lower surface, a perforated surface of the wing to form an opening for use in energizing the boundary layer, a means of pumping in communication with the upper surface opening to cause a flow therethrough, a prime mover in said passage and actuated by the flow of air therein to actuate the means of pumping, and means defining a barrier to substantial communication between the upper surface opening and the interior of the passage ahead of the location of the said prime mover in the passage and through a major portion of a spanwise extended wall of said passage.

20. In a wing formed with a nose portion closed to the head on impact of the wind along a major portion'of the span, said surface of thenose being in major part virtually rigidly joined to the central portion of the. wing, walls defining a passage having access to the impact pressure of the air flow and a rearward facing exit formed be-- tween the upper surface and an element of the lower surface of the wing, a perforated surface of the wing to form an opening for use in energizing the boundary layer, a means of pumping in communication with the said opening to cause aflow therethrough, and a prime mover in-said passage and deriving energy from the flow therein to actuate the means of pumping.

, EDWARD A. STALKER. 

